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| MPPP031 | The CERN-SPS Experiment on Microwave Transmission Through the Beam Pipe | electron, resonance, injection, dipole | 2212 | ||
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Funding: Ministry for Education, Science and Culture, Austria. |
In the CERN SPS microwave transmission measurements through beampipe sections with a length of 30 m and 7 m meter respectively have been carried out in the frequency range 2-4 GHz since spring 2003. Here we report on new results obtained with improved measurement techniques during the 2004 run. Observation techniques include a fast real time scope, spectrum analyser IF and video output signal registration and baseband signal observation using a PC soundcard. The unexpected beam induced amplitude modulation has been confirmed on all kinds of available beams including single bunches. It was found that there is a correlation between the amount of beam induced signal attenuation and the beam losses registered by external scintillators. Potential theoretical models are discussed. |
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| TPAT055 | On Start to End Simulation and Modeling Issues of the Megawatt Proton Beam Facility at PSI | simulation, space-charge, injection, proton | 3319 | ||
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At the Paul Scherrer Institut (PSI) we routinely extract a one megawatt (CW) proton beam out of our 590 MeV Ring Cyclotron. In the frame of the ongoing upgrade program, large scale simulations have been undertaken in order to provide a sound basis to assess the behaviour of very intense beams in cyclotrons. The challenges and attempts towards massive parallel three dimensional start-to- end simulations will be discussed. The used state of the art numerical tools (mapping techniques, time integration, parallel FFT and finite element based multigrid Poisson solver) and their parallel implementation will be discussed. Results will be presented in the area of: space charge dominated beam transport including neighbouring turns, eigenmode analysis to obtain accurate electromagnetic fields in large the rf cavities and higher order mode interaction between the electromagnetic fields and the particle beam. For the problems investigated so far a good agreement between theory i.e. calculations and measurements is obtained.
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| TPPE012 | Using the Orbit Tracking Code Z3CYCLONE to Predict the Beam Produced by a Cold Cathode PIG Ion Source for Cyclotrons under DC Extraction | emittance, plasma, ion, ion-source | 1297 | ||
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Experimental measurements of the emittance and luminosity of beams produced by a cold-cathode Phillips Ionization Guage (PIG) ion source for cyclotrons under dc extraction are reviewed. (The source being studied is of the same style as ones that will be used in a series of 250 MeV proton cyclotrons being constructed for cancer therapy by ACCEL Inst, Gmbh, of Bergisch Gladbach, Germany.) The concepts of 'plasma boundary' and 'plasma temperature' are presented as a useful set of parameters for describing the initial conditions used in computational orbit tracking. Experimental results for r-pr and z-pz emittance are compared to predictions from the MSU orbit tracking code Z3CYCLONE with results indicating that the code is able to predict the beam produced by these ion sources with adequate accuracy such that construction of actual cyclotrons can proceed with reasonably prudent confidence that the cyclotron will perform as predicted.
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| TPPE033 | A Comparison of Electrostatic and Magnetic Focusing of Mixed Species Heavy Ion Beams at NSCL/MSU | sextupole, focusing, ion, quadrupole | 2281 | ||
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Funding: This work has been supported by National Science Foundation under grant PHY-0110253. |
Experience at the National Superconducting Cyclotron Laboratory has shown the first focusing element after the electron cyclotron resonance ion source (ECRIS), before the beam is analyzed by a magnetic dipole, to be critical to subsequent beam transport and matching. Until 2004, both ion sources at the NSCL used a solenoid as this first focusing element. Observation of hollow beam formation led to further analysis and the decision to replace the solenoid with an electrostatic quadrupole triplet on a test basis [1]. Substantial increases in net cyclotron output were achieved, leading us to adopt electrostatic quadrupole focusing as the permanent configuration. In addition, a sextupole magnet was installed in this beam line. Motivations for these changes and results of operating experience are discussed. |
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| TOPD001 | SC Cyclotron and RIB Facilities in Kolkata | ion, target, linac, rfq | 89 | ||
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The superconducting cyclotron under construction at this Centre has bending limit (K-bend) of 520 and focusing limit (K-foc) of 160. It is being constructed, primarily, for nuclear physics experiments with heavy ion beams at intermediate energies. The 100-ton main magnet is currently in the commissioning phase with the main coil already at 4.2K temperature. Magnetic field measurements will be carried out over the next several months. All other systems of the cyclotron are in an advanced stage of fabrication or development. We plan to start assembly of the complete cyclotron around the end of 2005. In the phase-I of the project one beam line has been provided. Construction of three more beam lines and various experimental facilities for nuclear physics as well as irradiation experiments has also been funded and the work is well on its way. An ISOL type Radioactive Ion Beam (RIB) facility is being built with the existing K=130 room temperature cyclotron, VEC, as the primary beam source. In-beam RIB production as well as release measurements have been initiated using the VEC beam. The two-ion-source charge breeder consists of a surface ion source and a 6.4 GHz ECR source. The latter has been commissioned. A low beta RFQ to accelerate RIBs to 86 keV/u energy is being fabricated and the cold model tests completed. Design of first three linac tanks, for acceleration up to 400 keV/u, has been finalized and cold model for the first tank has been fabricated. In this talk status of both the projects will be presented.
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| WPAE008 | Redesign of a Low Energy Probe Head | emittance, simulation, proton, injection | 1105 | ||
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The present situation of the low energy probe L·102 in TRIUMF cyctron is that the thickness of finger 5 is uniform in the radial direction and its weight which amounts to ~447 g is affecting its re-circulating ball mechanism and causing it to fall below the median plane over its range of movement (13.890 to 161.515 inch). We first made simulations to determine the optimum thickness of the probe head vs the radial length so as to reduce its weight. And then, we compared the simulation results with experimental measurements made. Finally, we calculated the temperature rise caused by the beam power dumped on the probe, and figured out the maximum beam current that can be dumped on the finger.
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| WPAE011 | Electrostatic Deflectors: New Design for High Intensity Beam Extraction | septum, cathode, extraction, vacuum | 1245 | ||
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Funding: INFN-LNS Catania |
During the last years big effort was devoted to increase the electrostatic deflectors’ reliability; this provided a better comprehension of the most significant effects concerning their working conditions. Deflectors were checked during the normal operation of the K800 Superconducting Cyclotron (CS) at LNS, at the operating pressure of 1 10-6 mbar and a magnetic field of 3.5 T, the maximum cathodes voltage was –60kV (120 kV/cm). The maximum extracted beam power was, up to now, 100 W; it is foreseen to extract up to 500 W. In this contribution we present the study, the tests and the design of a new water cooled electrostatic deflector. Particular effort was applied to optimise the beam extraction efficiency, the thermal dissipation, and the mechanical stability. In particularly we implemented new insulators, new anodised aluminium cathodes, new Ta septum, new voltage and water feedthroughs and a more efficient cooling system. All these improvements were performed to increase the mean time between failure and the beam current stability. |
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| WPAE062 | AC Power Supply for Wobbler Magnet of the MC-50 Cyclotron | power-supply, ion, target, radiation | 3576 | ||
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The MC-50 cyclotron (k=50) produces the ion beam for nuclear physics, chemistry, and applied researches in Korea. It has a small beam diameter with Gaussian beam shape, whereas many users want a beam irradiation on a large target. A wobbler magnet and an AC power supply were designed and constructed to meet the users’ requirement. The power supply has two independently operating channels for the vertical and horizontal coils of the wobbler magnet. The frequency of the AC power supply for both coils is programmable from 1 to 20 Hz in a step of 1 Hz, and the maximum rms output current is 12 A. Various properties of the power supply and experimental results are given in the paper.
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| WPAT001 | HFSS Simulation of Vacuum Tube RF Power Amplifiers | booster, simulation, vacuum, insertion | 767 | ||
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Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada. |
Development and upgrade of rf power amplifiers require comprehensive calculations to predict and optimize various parameters of the system before hardware modifications are applied. ANSOFT HFSS code provides a powerful tool for 3D EM simulation of the amplifier output resonator comprising a vacuum tube as a passive element. Two examples of this kind of simulation applied for upgrade of the TRIUMF Cyclotron rf system are presented in this paper. |
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| WOPA002 | Experimental Results from the Small Isochronous Ring | space-charge, simulation, electron, focusing | 159 | ||
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Funding: Work supported by NSF Grant # PHY-0110253 and DOE Contract DE-AC05-84ER40150. |
The Small Isochronous Ring (SIR) is a compact, low-energy storage ring designed to investigate the beam dynamics of high-intensity isochronous cyclotrons and synchrotrons at the transition energy. The ring was developed at Michigan State University and has been operational since December 2003. It stores 20 keV hydrogen beams with a peak current of 10-20 microamps for up to 200 turns. The transverse and longitudinal profiles of extracted bunches are measured with an accuracy of approximately 1 mm. The high accuracy of the measurements makes the experimental data attractive for validation of multi-particle space charge codes. The results obtained in the ring show a fast growth of the energy spread induced by the space charge forces. The energy spread growth is accompanied by a breakup of the beam bunches into separated clusters that are involved in the vortex motion specific to the isochronous regime. The experimental results presented in the paper show a remarkable agreement with simulations performed with the code CYCO. In this paper, we discuss specifics of space charge effects in the isochronous regime, present results of experiments in SIR, and conduct a detailed comparison of the experimental data with results of simulations. |
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| RPAP013 | Characteristic Experimentations of Degrader and Scatterer at MC-50 Cyclotron | proton, target, simulation, monitoring | 1356 | ||
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Funding: This work is a part of the "Proton Engineering Frontier Project" which is sponsored by the Ministry of Science and Technology of Korea under "21C Frontier R&D Program." |
Building proton beam user facilities, especially deciding beam energy level, depends on the attached proton accelerator and users' needs. To adjust beam energy level, two methods are generally used. One is to directly adjust the beam in the accelerator. The other is to adjust beam energy after extracting from the accelerator. Degrader/Scatterer System has been installed in the MC-50 Cyclotron to adjust energy level of the beam used for various application fields. Its degrader and scatterer are made of Al foils and Au foils, respectively. Al thickness are 2, 1, 0.5, 0.3, 0.2, 0.1, 0.05, 0.03, 0.02, 0.01mm and Au thickness are 0.2, 0.1, 0.05, 0.03, 0.02, 0.01mm, respectively. In this study, suitable beam condition was adjusted through overlapping Al/Au foils of various thickness through simulation results. After that, LET(Linear Energy Transfer) value was indirectly acquired by measuring the bragg peak of the external beam through PMMA plastic Phantom and profile was measured by film dosimetry. |
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| RPAP014 | Uniform Irradiation Systems Using a Rotatable Stage for Test Facilities of PEFP | target, proton, simulation, dipole | 1383 | ||
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Funding: This work is a part of the "Proton Engineering Frontier Project" which is sponsored by the Ministry of Science and Technology of Korea under '21C Frontier R&D Program." |
A new irradiation facility has been developed using not only electric magnets but also a rotatable stage. Generally, the scanning method using magnet has been widely used in most of facilities. However, in this study another new methods have been developed: Three scanning method using rotatable stage have been proved to make uniform irradiation-as large as 20 cm in diameter with more than 90% uniformity. The mechanical wobbler system makes the same effect as the wobbler system. And the beam is swept along the spiral path with a fixed and variable angular frequency during the scanning in two spiral scanning systems, respectively. |
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| RPAP020 | Fixed Field Alternating Gradient Accelerators (FFAG) for Fast Hadron Cancer Therapy | proton, resonance, ion, acceleration | 1667 | ||
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Funding: * AMS supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF0009 |
Cancer accelerator therapy continues to be ever more prevalent with new facilities being constructed at a rapid rate. Some of these facilities are synchrotrons, but many are cyclotrons and, of these, a number are FFAG cyclotrons. The therapy method of "spot scanning” requires many pulses per second (typically 200 Hz), which can be accomplished with a cyclotron (in contrast with a synchrotron). We briefly review commercial scaling FFAG machines and then discuss recent work on non-scaling FFAGs, which may offer the possibility of reduced physical aperture and a large dynamic aperture. However, a variation of tune with energy implies the crossing of resonances during the acceleration process. A design can be developed such as to avoid intrinsic resonances, although imperfection resonances must still be crossed. Parameters of two machines are presented; a 250 MeV proton therapy accelerator and a 400 MeV carbon therapy machine. |
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| RPAP037 | Study of the Dynamics in a Linac Booster for Proton Therapy in the 30-62 MeV Energy Range | linac, proton, booster, coupling | 2494 | ||
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Funding: Istituto Nazionale di Fisica Nucleare (Naples, Milan and Bari). |
Recent results in accelerator physics have shown the feasibility of a coupling scheme between a cyclotron and a linac for proton acceleration. Cyclotrons with energies up to 30 MeV, mainly devoted to radioisotopes production, are available in a large number of medical centres. These two evidences have suggested the idea to study and design a linac booster able to increase the initial proton energy up to the values required for the treatment of tumors, like the ocular ones. Among the challenges in such a project one of the main ones is related to meet the requirement of having sufficient mean current for therapy from a given injection current coming from the cyclotron. In this paper we will review the rationale of the project in order to optimize the transmittance and to minimize the duty-cycle. In this frame we will discuss the basic design of a compact 3GHz linac with a new approach to the cavities used in a SCL (Side Coupled Linac) structure. |
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| RPAT045 | Beam Phase Detection for Proton Therapy Accelerators | proton, pick-up, acceleration, feedback | |||
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The industrial application of proton cyclotrons for medical applications has become one of the important contributions of accelerator physics during the last years. This paper describes an advanced vector demodulating technique used for non-destructive measurements of beam intensity and beam phase over 360°. A computer controlled I/Q-based phase detector with a very large dynamic range of 70 dB permits the monitoring of beam intensity, phase and eventually energy for wide range of beam currents down to –130 dBm. In order to avoid interference from the fundamental cyclotron frequency the phase detection is performed at the second harmonic frequency. A digital low pass filter with adjustable bandwidth and steepness is implemented to improve accuracy. With a sensitivity of the capacitive pickup in the beam line of 30 nV per nA of proton beam current at 250 MeV, accurate phase and intensity measurements can be performed with beam currents down to 3.3 nA.
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| RPPT043 | Commissioning of the Main Magnet of Kolkata K-500 Superconducting Cyclotron | vacuum, superconducting-magnet, power-supply, radio-frequency | 2765 | ||
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Main magnet of the K-500 superconducting cyclotron at Kolkata has been fully assembled in the cyclotron vault. The assembly includes alpha and beta superconducting coils inside the liquid helium chamber, coil tank for the outer vacuum, liquid nitrogen shield, support links, cryogenic instrumentation and 80 ton magnet frame forming the pill box structure. Cooling of the coils was started in mid-December. It took about three weeks to fill the liquid helium chamber - fully immersing the coils. All the four temperature sensors embedded in the coil are steady at about 4.4K. At this time the liquid nitrogen line for cooling the shield seems to show a leak. So, we are not cooling the shield. The helium liquefier/regrigerator of 200W capacity has been functioning well and so is the network of vacuum jacketted and liquid nitrogen cooled cryogenic transfer lines. Energization of the main magnet will begin soon. Magnetic field measurement set up is in place to start the mapping. In this presentation, our experiences with commissioning of the largest superconducting magnet in India, with stored energy 22 MJ at peak field of 6T, will be described. Some results of the magnetic field measurements will also be presented.
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| ROPC003 | RIKEN RI Beam Factory Project | ion, heavy-ion, extraction, acceleration | 320 | ||
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The world-top-class radioactive-isotope-beam (RIB) facility, which is called ?RI beam factory (RIBF)?, is under construction at RIKEN. This facility is based on the so-called ?in-flight RI beam separation? scheme. Late in 2006, a new high-power heavy-ion accelerator system consisting of a cascade of three ring cyclotrons with K=570 MeV (fixed frequency, fRC), 980 MeV (Intermediate stage, IRC) and 2500 MeV (superconducting, SRC), respectively, will be commissioned. This new accelerator system will boost energies of the output beams from the existing K540-MeV ring cyclotron up to 440 MeV/nucleon for light ions and 350 MeV/nucleon for very heavy ions. These energetic heavy-ion beams are converted into intense RI beams via the projectile fragmentation or in-flight fission of uranium ions by the superconducting isotope separator, BigRIPS, under construction. The combination of the SRC and BigRIPS will expand our nuclear world into presently unreachable region. Major experimental installations are under priority discussion as the second phase program. Construction of the second phase is expected to start in 2006.
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| FOAC003 | New Concepts in FFAG Design for Secondary Beam Facilities and Other Applications | proton, ion, resonance, acceleration | 261 | ||
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Fixed Field Alternating Gradient accelerators offer much higher acceptances and repetition rates - and therefore higher beam intensities - than synchrotrons, at the cost of more complicated magnet and rf cavity designs. Perhaps because of the difficulty and expense anticipated, early studies never progressed beyond the stage of successful electron models, but in recent years, with improvements in magnet and rf design technology, FFAGs have become the focus of renewed attention. Two proton machines have now been built, and three more, plus a muon phase rotator, are under construction. In addition, more than 20 designs are under study for the acceleration of protons, heavy ions, electrons and muons, with applications as diverse as treating cancer, irradiating materials, driving subcritical reactors, boosting high-energy proton intensity, and producing neutrinos. Moreover, it has become apparent that FFAG designs need not be restricted to the traditional 'scaling' approach, in which the orbit shape, optics and tunes are kept fixed. Dropping this restriction has revealed a range of interesting new design possibilities. This paper will review the various approaches being taken.
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| FPAE032 | ORIC Beam Energy Increase | extraction, septum, proton, ion | 2257 | ||
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Funding: Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05=00OR 22725. |
The detection of and solution to a beam interference problem in the Oak Ridge Isochronous Cyclotron (ORIC) extraction system has yielded a 20% increase in the proton beam energy. The beam from ORIC was designed to be extracted before the nu r equal one resonance. Most cyclotrons extract after the nu r equal one resonance, thus getting more usage of the magnetic field for energy acceleration. We have now determined that the electrostatic deflector septum interferes with the last accelerated orbit in ORIC, with the highest extraction efficiency obtained near the maximum nu r value. This nu r provides a rotation in the betatron oscillation amplitude that is about the same length as the electrostatic septum thus allowing the beam to jump over the interference problem with the septum. With a thinned septum we were able to tune the beam through the nu r equal one resonance and achieve a 20% increase in beam energy. This nu r greater than one extraction method may be desirable for very high field cyclotrons since it provides ten times the clearance at extraction compared to dee voltage gain, thus allowing the possibility of utilizing a magnetic extractor. |
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| FPAE035 | Steps Towards a 3 mA, 1.8 MW Proton Beam at the PSI Cyclotron Facility | target, injection, simulation, space-charge | 2405 | ||
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The PSI Cyclotron Facility produces routinely a 1.8-1.9 mA proton beam at 590 MeV. The beam power reaches 1.1 MW at the the pion production targets and 0.7 MW at the neutron spallation target SINQ. The accelerator complex will be analysed in respect to his potential for future improvements. The ongoing developments aiming to increase the beam intensity to 3 mA and hence the beam power to 1.8 MW will be discussed. Smooth extrapolations of the observed machine parameters as well as recent advances in the theoretical treatment of space charge dominated beams show that this goal can be achieved with available technologies. IA new RF-cavity operated at a voltage in excess of 1 MV has been successfully tested and installed in the Ring Cyclotron. Bunchers for the low energy and the medium energy transfer lines are in the design phase. A conceptual study of new accelerating cavities to replace the obsolete flattop-cavities of the Injector Cyclotron has been performed. While the upgrade of the Ring Cyclotron with four new cavities will be completed in 2008, it is still an open question whether this accelerator will be operated in the "round beam" mode like the Injector Cyclotron or with an upgraded flattopping system.
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| FPAE051 | Performance of a CW RFQ Injector for the IUCF Cyclotron | proton, rfq, ion-source, ion | 3179 | ||
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Funding: The State of Indiana, Indiana University, and the DOE (Grant No DE-FG-02000ER62966) supported this work. |
A 750 keV RFQ proton pre-injector was installed in place of a 600 keV Cockroft-Walton high voltage terminal for the IUCF k220 Cyclotron.* The pre-injector consists of a 20 keV microwave ion source and LEBT, a unique design 750 keV CW RFQ, and a short transfer beam line to the k15 injector cyclotron center region.** This pre-injector system was installed and commissioned in June of 2003 and is now in routine service as the sole injection system to the cyclotrons. This contribution will discuss the performance of the CW RFQ pre-injector and the transmission properties of the beam through the cyclotrons. *D.L.Friesel, et al., App. of Acc. in Res. and Ind., eds. J.L. Duggan and I.L. Morgan, Denton, 651(2000). **V.P. Derenchuk, et al., 2003 Particle Accelerator Conference, Portland, OR, (2003), edited by A. Jackson and E. Lee. |
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| FPAE068 | Charge Strippers in the RIKEN RI-Beam Factory | ion, injection, heavy-ion, factory | 3751 | ||
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In the RIKEN RI-Beam Factory, ions from hydrogen to uranium are planned to be accelerated by four cyclotrons and linacs using four stripper sections. The charge stripping schemes for typical ions and the selection of the charge strippers are described. The results of the measurements on charge state fractions are presented.
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| FPAE072 | RF-Kicker System for Secondary Beams at NSCL/MSU | kicker, secondary-beams, ion, quadrupole | 3880 | ||
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The design and construction of a radio frequency (RF) kicker system at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU) has been proposed. This RF kicker system will be used to purify secondary beams of rare isotopes after the existing A1900 Fragment Separator and will open a wide range of possibilities for new experiments at the forefront of nuclear science. The proposed system is studied as an efficient alternative to the traditional approach using Wien Filter. Rare neutron deficient secondary beams are challenging to purify because of the presence of intense contaminants that cannot be removed by the traditional energy loss method. However, velocity differences resulting in time-of-flight differences can be used for the effective separation of the beams transversely using the time-varying electromagnetic fields of the RF kicker. Its technical design will be presented together with the beam dynamics analysis of a secondary beam in realistic 3D electromagnetic fields. The expected purification improvement of the exotic beams for the foreseen nuclear physics experiments will be shown in details.
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| FPAP011 | New Vortices in Axisymmetric Beams in Inhomogeneous Magnetic Field | electron, vacuum, plasma | |||
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We analyzed localized vortices in non-neutral inhomogeneous by density and velocity electron beams propagating in vacuum along the inhomogeneous external magnetic field. These vortices distinguish from vortices, which used in Golub Yu.Ya. et al. and Golub Yu.Ya. because of inhomogeneous external magnetic field. Also new types of vortex are obtained by new solution method of nonlinear equations.** The new method is development of a method described in Golub Yu.Ya. That method distinguish from standard Larichev-Reznik or Reznik method, which used in Golub Yu.Ya. et al. It has been found new expression for electric field potential of vortex in a wave frame. The expression is axisymmetric in a wave frame. New vortices are new solitons in the inhomogeneous external magnetic field.
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*Golub Yu.Ya. et al., in Nonlinear world: IV Intern. Workshop on Nonlin. and Turbul. Proc. in Phys., (ed. by V.G. Bar'yakhtar et al.) World Scientific Publishing Co. Pte. Ltd., Singapore, 1990, vol. 2, p. 857. **Golub Yu.Ya., Proceedings of EPAC 2002, Paris, France, p. 1253. |
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